Powered stapling device with rack release

ABSTRACT

A powered handle assembly includes a motor assembly, a rack, a shaft, and a pinion that couples the motor assembly to the rack. The shaft supports the pinion and is movable to move the pinion from a first position engaged with the rack to a second position disengaged from the rack to facilitate manual retraction of the rack.

FIELD

This disclosure is directed to powered surgical devices and, more particularly, to powered surgical stapling devices.

BACKGROUND

Various types of surgical devices used to endoscopically treat tissue are known in the art, and are commonly used, for example, for closure of tissue or organs in transection, resection, and anastomoses procedures, for occlusion of organs in thoracic and abdominal procedures, and for electrosurgically fusing or sealing tissue.

One example of such a surgical device is a surgical stapling device. Typically, surgical stapling devices include a tool assembly having an anvil assembly and a cartridge assembly, and a drive assembly. Typically, the drive assembly includes a flexible drive beam and a clamp member that is supported on a distal end of the drive beam. The drive assembly is movable to advance the clamp member through the tool assembly to approximate the cartridge and anvil assemblies and to advance an actuation sled through the cartridge assembly to eject staples from the cartridge assembly.

Surgical stapling devices can be manually actuated devices in which a clinician squeezes a trigger to actuate the stapling device, or powered stapling devices in which a clinician activates a motor within the stapling device to actuate the stapling device. Although powered stapling devices require less force to operate, difficulties may arise when the device loses power or components of the device break. In such instances, the device can remain clamped about tissue preventing removal of the device from a patient.

A continuing need exists in the art for a powered stapling device that includes a drive assembly that can be manually retracted when power is lost or when the device is not operational.

SUMMARY

A surgical device includes a powered handle assembly having a motor assembly, a rack, a shaft, and a pinion that couples the motor assembly to the rack. The shaft supports the pinion and is movable to move the pinion from a first position engaged with the rack to a second position disengaged from the rack to facilitate manual retraction of the rack.

One aspect of the disclosure is directed to a powered handle assembly for a surgical device including a housing, a gear casing, a motor assembly, a rack, a shaft, and a pinion. The housing defines a cavity. The gear casing is supported within the cavity of the housing and defines a cavity and a longitudinal channel that extends through the cavity. The motor assembly includes an output shaft and a drive gear that is secured to the output shaft. The motor assembly is secured to the gear casing, and the drive gear is positioned within the cavity of the gear casing. The rack is received within the longitudinal channel of the gear casing and is movable through the cavity of the gear casing between retracted and advanced positions. The shaft extends through the cavity of the gear casing and is axially movable between first and second positions. The pinion is coupled to the shaft and is received within the cavity of the gear casing. The pinion is movable within the cavity of the gear casing, in response to movement of the shaft between its first and second positions, from a first position in which the pinion is engaged with the rack to a second position in which the pinion is disengaged from the rack.

Other aspects of the disclosure are directed to a surgical device including a powered handle assembly, an adapter assembly, and a tool assembly. The powered handle assembly includes a housing, a gear casing, a motor assembly, a rack, a shaft, and a pinion. The housing defines a cavity. The gear casing is supported within the cavity of the housing and defines a cavity and a longitudinal channel that extends through the cavity of the gear casing. The motor assembly includes an output shaft and a drive gear that is secured to the output shaft. The motor assembly is secured to the gear casing, and the drive gear is positioned within the cavity of the gear casing. The rack is received within the longitudinal channel of the gear casing and is movable through the cavity of the gear casing between retracted and advanced positions. The shaft extends through the cavity of the gear casing and is axially movable between first and second positions. The pinion is coupled to the shaft and is received within the cavity of the gear casing. The pinion is movable within the cavity of the gear casing, in response to movement of the shaft between its first and second positions, from a first position in which the pinion is engaged with the rack to a second position in which the pinion is disengaged from the rack. The adapter assembly includes a firing rod and has a proximal portion and a distal portion. The proximal portion of the adapter assembly is coupled to the handle assembly. The firing rod is coupled to the rack and is movable between retracted and advanced positions in response to movement of the rack between its retracted and advanced positions. The tool assembly is supported on the distal portion of the adapter assembly.

Other aspects of the disclosure are directed to a powered handle assembly for a surgical device including a housing, a motor assembly, a rack, a shaft, and a pinion. The housing defines a cavity. The motor assembly includes an output shaft and a drive gear secured to the output shaft. The rack is received within the cavity of the housing and is movable between retracted and advanced positions. The shaft extends through the cavity of the gear casing and is axially movable between first and second positions. The pinion is coupled to the shaft and is movable, in response to movement of the shaft between its first and second positions, from a first position in which the pinion is engaged with the rack to a second position in which the pinion is disengaged from the rack.

In aspects of the disclosure, the shaft is rotatably fixed to the gear casing.

In some aspects of the disclosure, a biasing member is positioned within the cavity of the gear casing to urge the pinion towards its first position.

In certain aspects of the disclosure, the drive gear is engaged with the pinion such that rotation of the drive gear causes rotation of the pinion.

In aspects of the disclosure, the motor assembly includes a motor having a motor shaft, a universal joint, a joint housing, and the output shaft, and the universal joint couples the motor shaft to the output shaft.

In some aspects of the disclosure, the motor shaft defines a first axis, and the output shaft defines a second axis, and the first axis defines an acute angle with the second axis.

In certain aspects of the disclosure, the output shaft of the motor assembly supports a first bevel gear, and the shaft supports a second bevel gear that is engaged with the first bevel gear such that rotation of the first bevel gear causes rotation of the second bevel gear.

In aspects of the disclosure, the second bevel gear is fixedly secured to the shaft such that rotation of the second bevel gear causes rotation of the shaft and of the pinion.

In some aspects of the disclosure, the gear casing includes side walls, and each of the side walls supports a bearing.

In aspects of the disclosure, the shaft is rotatably supported between the bearings on the gear casing.

Other features of the disclosure will be appreciated from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of the disclosed stapling device are described herein below with reference to the drawings, wherein:

FIG. 1 is a side perspective view of a first version of a stapling device according to aspects of the disclosure with the stapling device in a non-articulated, unclamped position;

FIG. 2 is a side perspective view of the handle assembly of the stapling device shown in FIG. 1 with a housing half-section removed;

FIG. 3 is an exploded side perspective view of internal components of the handle assembly shown in FIG. 3 ;

FIG. 4 is a cross-sectional view taken along section line 4-4 of FIG. 2 ;

FIG. 5 is a cross-sectional view taken along section line 5-5 of FIG. 4 ;

FIG. 6 is a cross-sectional view taken along section line 6-6 of FIG. 5 ;

FIG. 7 is a side perspective view of the motor assembly of the stapling device shown in FIG. 1 with a joint casing shown in phantom;

FIG. 8 is a side perspective view of a reload assembly of the stapling device shown in FIG. 1 in the clamped and fired position;

FIG. 9 is a cross-sectional view taken along section line 9-9 of FIG. 8 ;

FIG. 10 is a cross-sectional view through a portion of the handle assembly shown in FIG. 1 with the stapling device in the clamped and fired position;

FIG. 11 is a side perspective view of a portion of the handle assembly shown in FIG. 1 as the stapling device is manually retracted from the clamped and fired position;

FIG. 12 is an alternate version of the handle assembly of the stapling device shown in FIG. 1 including the motor assembly shown in FIG. 11 with an alternate version of the rotating shaft;

FIG. 13 is a side perspective view of the rotating shaft of the handle assembly shown in FIG. 12 ;

FIG. 13A is perspective view of the handle assembly shown in FIG. 12 with a housing of the handle assembly removed and a pinion in a first position;

FIG. 13B is a perspective view of the handle assembly shown in FIG. 12 with the housing and gear casing removed and the pinion in a first position;

FIG. 13C is a cross-sectional view taken along section line 13C-13C of FIG. 13A with the pinion in the first position;

FIG. 13D is a cross-sectional view taken along section line 13C-13C of FIG. 13A with the pinion in a second position;

FIG. 14 is an alternate version of the handle assembly of the stapling device shown in FIG. 1 with a housing of the handle assembly shown in phantom;

FIG. 15 is an assembled, side perspective view of the internal components of the handle assembly shown in FIG. 14 ;

FIG. 16 is an exploded side perspective view of internal components of the handle assembly shown in FIG. 15 ;

FIG. 17 is a cross-sectional view taken along section line 17-17 of FIG. 15 ;

FIG. 18 is a side cross-sectional view of the drive assembly of the handle assembly of the stapling device shown in FIG. 15 in the fired position;

FIG. 18A is a side cross-sectional view through the drive assembly of FIG. 14 illustrating the manual retract mechanism in the unlocked position;

FIG. 19 another alternate version of the handle assembly of the stapling device shown in FIG. 1 with a housing of the handle assembly shown in phantom;

FIG. 20 is a side perspective view of a motor assembly and a drive assembly of the handle assembly shown in FIG. 19 with a gear casing removed;

FIG. 21 is an exploded side perspective view of the drive assembly of the handle assembly shown in FIG. 19 ;

FIG. 22 is a side perspective view of the motor assembly and the drive assembly shown in FIG. 20 with the motor assembly actuated to advance the drive assembly;

FIG. 23 is a plan view of the motor assembly and the drive assembly shown in FIG. 23 with the motor assembly engaged with the drive assembly; and

FIG. 24 is a plan view of the motor assembly and the drive assembly shown in FIG. 23 with the motor assembly disengaged with the drive assembly.

DETAILED DESCRIPTION

The disclosed surgical device will now be described in detail with reference to the drawings in which like reference numerals designate identical or corresponding elements in each of the several views. However, it is to be understood that the aspects of the disclosure are merely exemplary of the disclosure and may be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the disclosure in virtually any appropriately detailed structure. In addition, directional terms such as front, rear, upper, lower, top, bottom, and similar terms are used to assist in understanding the description and are not intended to limit the disclosure.

In this description, the term “proximal” is used generally to refer to that portion of the device that is closer to a clinician, while the term “distal” is used generally to refer to that portion of the device that is farther from the clinician. In addition, the term “endoscopic” is used generally to refer to endoscopic, laparoscopic, arthroscopic, and/or any other procedure conducted through a small diameter incision or cannula. Further, the term “clinician” is used generally to refer to medical personnel including doctors, nurses, surgeons, and support personnel.

This disclosure is directed to a surgical device that includes a powered handle assembly having a motor assembly, a rack, a spur gear, and a manual retract mechanism. The spur gear is movable from a position engaged with the motor assembly and the rack to a positioned disengaged from the motor assembly and engaged with the rack to facilitate manual retraction of the rack. This disclosure is also directed to a surgical device that includes a powered handle assembly having a motor assembly, a rack, a shaft, and a pinion that couples the motor assembly to the rack. The shaft supports the pinion and is movable to move the pinion from a first position engaged with the rack to a second position disengaged from the rack to facilitate manual retraction of the rack.

FIG. 1 illustrates a surgical device shown generally as stapling device 10 which includes a handle assembly 12, an elongate body or adapter assembly 14, and a tool assembly 16. The handle assembly 12 includes a housing 18 that forms a stationary handle portion 18 a, an articulation lever 19, and actuation buttons 20. The adapter assembly 14 defines a longitudinal axis “X” and includes a proximal portion 24 that is coupled to the handle assembly 12, and a distal portion 26 that supports the tool assembly 16. The tool assembly 16 is secured to the distal portion 26 of the adapter assembly 14 by a pivot member 28 that defines an axis “Y” that is transverse to the longitudinal axis “X”. The articulation lever 19 is operatively coupled to the tool assembly 16 via an articulation linkage (not shown) such that manipulation of the articulation lever 19 causes articulation of the tool assembly 16 about the axis “Y” between a non-articulated position in which the tool assembly 16 is aligned with the longitudinal axis “Y” and non-articulated positions in which a longitudinal axis of the tool assembly and the longitudinal axis “X” define acute angles. The adapter assembly 14 is supported within a rotation knob 30 that is rotatably coupled to a distal portion of the handle assembly 12. The rotation knob 30 is manually rotatable about the longitudinal axis “X” to rotate the adapter assembly 14 and the tool assembly 16 about the longitudinal axis “X”. The actuation buttons 20 control operation of the different functions of the stapling device 10 including clamping and firing of the stapling device 10.

In aspects of the disclosure, the tool assembly 16 forms part of a reload assembly 32 that includes a proximal body portion 34 and the tool assembly 16. The proximal body portion 34 of the reload assembly 32 forms an extension of the adapter assembly 14 and includes a proximal end that is adapted to be releasably coupled to a distal end of the adapter assembly 14 and a distal end that supports the tool assembly 16 for articulation. In aspects of the disclosure, the tool assembly 16 can be fixedly coupled to a distal portion of the adapter assembly 14.

In aspects of the disclosure, the housing 18 of the handle assembly 12 is formed from half-sections that are coupled together such as by welding or using screws to define a cavity 38 (FIG. 2 ) that receives internal components of the handle assembly 12 which are described in further detail below. The housing 18 defines an upper opening 40 that provides access to the internal components of the handle assembly 12. The upper opening 40 is enclosed by a cover 42 that is removably supported within the upper opening 40.

FIGS. 2 and 3 illustrate the internal components of the handle assembly 12 which include a gear casing 44, a motor assembly 46, a rack 48, a firing rod 50, a manual retract mechanism 52 and intermediate spur gear 54, and a drive gear 56. The gear casing 44 is secured within the cavity 38 of the housing 18 using screws or the like and defines a first cavity 60 and a second cavity 62 that intersect with each other and a longitudinally extending channel 64. The first cavity 60 of the gear casing 44 receives the drive gear 56 and the second cavity 62 of the gear casing 44 receives the intermediate spur gear 54. The drive gear 56 and the intermediate spur gear each include gear teeth that mesh such that rotation of the drive gear 56 within the first cavity 60 causes corresponding rotation of the intermediate spur gear 54 within the second cavity 62. The rack 48 is received within the channel 64 of the gear casing 44 and includes gear teeth that mesh with the gear teeth of the intermediate spur gear 54. When the drive gear 56 is rotated to rotate the intermediate spur gear 54, engagement between the intermediate spur gear 56 and the rack 48 causes the rack 48 to move longitudinally through the channel 64 in the gear casing 44.

The motor assembly 46 includes an output shaft 70 (FIG. 4 ) that is secured to the drive gear 56 and can be activated via the actuation buttons 20 (FIG. 1 ) to rotate the drive gear 56. In aspects of the disclosure, the motor assembly 46 is positioned within a portion of the cavity 38 of the housing 18 defined by the stationary handle portion 18 a. The motor assembly 46 includes a mounting bracket 72 that is secured to the gear casing 44 with screws 74 such that the drive gear 56 is received within the second cavity 62 of the gear casing 44.

FIGS. 3-6 illustrate the manual retract mechanism 52 which includes a rotating shaft 78, a crank lever 80, and a grip member 82. The crank lever 80 includes a central hub portion 84 that defines a through bore 86 that receives the rotating shaft 78. The through bore 86 includes a cylindrical portion 86 a and a rectangular portion 86 b. The crank lever 80 also includes a lever portion 88 that defines a slot 90 and forms a clevis 92. The grip member 82 is supported within the clevis 92 by a pivot member 94 and is pivotable between a first position located within the slot 90 and a second position extending orthogonally from the lever portion 88.

The rotating shaft 78 includes a head portion 96 and a shaft portion 98 that extends downwardly from the head portion 96 as viewed in FIG. 5 through the through bore 86 in the crank lever 80. The shaft portion 98 includes a first rectangular portion 100, a cylindrical portion 102, and a second rectangular portion 104. The second rectangular portion 104 includes spaced annular grooves 106 and 108 that receive C-clips 110 and 112, respectively. The intermediate spur gear 54 is received about the second rectangular portion 104 of the rotating shaft 78 atop the C-clip 112 within the first cavity 60 of the gear casing 44. The C-clip 112 is positioned externally of the first cavity 60 and secures the rotating shaft 78 to the gear casing 44. Although the rotating shaft 78 is shown to have first and second rectangular portions, it is envisioned that other shaft configurations are envisioned.

The gear casing 44 defines first and second openings 114 and 116 that communicate with upper and lower ends of the first cavity 60 of the gear casing 44. The cylindrical portion 102 of the rotating shaft 78 is received within the first opening 114 of the gear casing 44 and the second rectangular portion 104 of the rotating shaft 78 extends through the second opening 116 of the gear casing 44. The C-clip 110 (FIG. 5 ) is secured to the lower end of the second rectangular portion 104 of the rotating shaft 78 adjacent a lower surface of the gear casing 44 and the C-clip 112 is secured to the second rectangular portion 104 of the rotating shaft 78 within the first cavity 60 of the gear casing 44. The C-clips 110 and 112 secure the intermediate spur gear 54 to the rotating shaft 78 and secure the rotating shaft 78 to the gear casing 44. The second rectangular portion 104 of the rotating shaft 78 is received within a rectangular bore in the intermediate spur gear 54 to rotatably fix the intermediate spur gear 54 to the rotating shaft 78.

The intermediate spur gear 54 is received within the first cavity 60 of the gear casing 44 and is movable within the first cavity between a first or lower position and a second or upper position. In the lower position (FIG. 5 ), the teeth of the intermediate spur gear 54 simultaneously engage the teeth of the rack 48 and the teeth of the drive gear 56. In the upper position, the teeth of the intermediate spur gear 54 engage only the teeth of the rack 48.

The manual retract mechanism 52 includes a biasing member 120 that is positioned between an upper surface of the intermediate spur gear 54 and the inner surface of the gear casing 44. The biasing member 120 urges the intermediate spur gear 54 towards its lower position in which the intermediate spur gear 54 is engaged with both the drive gear 56 and the rack 48. In some aspects of the disclosure, a washer 122 is positioned between an upper surface of the biasing member 120 and the inner surface of the gear casing 44. In certain aspects of the disclosure, the biasing member 120 includes a coil spring. It is envisioned that other types of biasing members could be incorporated into the stapling device 10 (FIG. 1 ).

The rack 44 includes a distal portion that is coupled to the firing rod 50. In aspects of the disclosure, the proximal portion of the firing rod 50 is formed with a head 124 (FIG. 3 ) that has a diameter that is larger than a body of the firing rod 50, and the distal portion of the rack 48 defines a slot 128. The head 124 of the firing rod 50 is received within the slot 128 of the rack 48 to couple the firing rod 50 to the rack 48 such that longitudinal movement of the rack 48 causes longitudinal movement of the firing rod 50. The coupling of the head 124 and the slot 128 allows the firing rod 50 to rotate in relation to the rack 48.

In some aspects of the disclosure, the manual retract mechanism 52 includes a base member 130 that defines a circular bore 132 (FIG. 3 ). The base member 130 is secured to an upper surface of the gear casing 44 and the hub portion 84 of the crank lever 80 is aligned within the circular bore 132. The crank lever 80 is movable from a lowered position to a raised position. In the lowered position, the hub portion 84 of the crank lever 80 is received within the circular bore 132 and in the raised position, the hub portion 84 of the crank lever 80 is positioned above the circular bore 132 of the base member 130.

The head 96 of the rotating shaft 78 of the manual retract mechanism 52 is received within the bore 86 of the crank lever 80. When the crank lever 80 is in its lowered position, the cylindrical portion 102 of the rotating shaft 78 is received within the rectangular portion 86 b (FIG. 5 ) of the through bore 86 of the crank lever 80. In this position, the rotating shaft 78 can rotate within the through bore 86 of the crank lever 80 without causing rotation of the crank lever 80. When the crank lever 80 is moved to its raised position, the first rectangular portion 100 (FIG. 3 ) of the rotating shaft 78 is received within the rectangular portion 86 b of the through bore 86 of the crank lever 80. In this position, rotation of the crank lever 80 causes corresponding rotation of the rotating shaft 78, and thus, rotation of the intermediate spur gear 54. The head 96 of the rotating shaft 78 has a diameter that is larger than the width of the rectangular portion 86 b of the through bore 86 of the crank lever 80. Thus, movement of the crank lever 80 to its raised position causes the rotating shaft 78 to move to its upper position in which the teeth of the intermediate spur gear 54 are only engaged with the teeth of the rack 48.

FIG. 7 illustrates the motor assembly 46 which includes a motor 142, a motor shaft 144, a universal joint 146, a joint housing 148 and the motor assembly output shaft 70. As described above, the motor assembly output shaft 70 supports the spur gear 54. The universal joint 146, e.g., a Cardan joint, couples the motor shaft 144 to the motor assembly output shaft 70 to translate rotation of the motor shaft 144 into rotation of the motor assembly output shaft 70. The universal joint 144 allows a longitudinal axis of the motor shaft 144 to be positioned at an angle to a longitudinal axis of the motor assembly output shaft 70. The motor 142 of the motor assembly 46 is supported within the stationary handle portion 18 a of the handle assembly 12. The universal joint 146 allows the stationary handle portion 18 a (FIG. 2 ) to be angled in relation to the longitudinal axis of the stapling device 10 (FIG. 1 ) to provide a more ergonomic grip configuration on the handle assembly 12 of the stapling device 10.

The handle assembly 12 (FIG. 1 ) also includes one or more batteries 140 (FIG. 2 ) which are received within the cavity 38 of the housing 18 of the handle assembly 12. The batteries 140 provide power to the motor assembly 46 via the actuation switches 20 (FIG. 1 ) and control circuitry (not shown), e.g., a printed circuit board and one or more controllers, positioned within the handle assembly 12 to control firing of the stapling device 10.

FIGS. 4-6 illustrate the handle assembly 12 of the stapling device 10 (FIG. 1 ) with the stapling device 10 in an unclamped position prior to firing of the stapling device. In this position, the rack 48 is in a retracted position within the channel 64 of the gear casing 44 and the intermediate spur gear 54 is in its lowered position and is engaged with the rack 48 and the drive gear 56.

FIGS. 8 and 9 illustrate the reload assembly 32 when the stapling device 10 is in a fired position. As described above, the reload assembly 32 includes the tool assembly 16 and the proximal body portion 34. In aspects of the disclosure, the tool assembly 16 includes an anvil assembly 150 and a cartridge assembly 152. The cartridge assembly 152 includes a staple cartridge 154 that supports a plurality of staples and pushers (not shown), and an actuation sled 156. The proximal body portion 34 includes a drive assembly 158 that includes a flexible beam 160 and a working end 162. The working end 162 of the drive assembly 158 has an I-beam configuration and is secured to a distal end portion of the flexible beam 160. The flexible beam 160 has a proximal end portion that is releasably coupled to a distal portion of the firing rod 50. When the firing rod 50 is moved from a retracted position to an advanced position, the drive assembly 158 moves from a retracted position to an advanced position to move the working end 162 of the drive assembly 158 through the tool assembly 16 to advance the actuation sled 156 through the tool assembly 16. As the actuation sled 156 moves through the tool assembly 16, the actuation sled 156 engages the pushers (not shown) to eject staples (not shown) from the staple cartridge 154 into the anvil assembly 150. In the fired position, the working end 162 of the drive assembly 158 and the actuation sled 156 are in their advanced positions within the tool assembly and the tool assembly 16 is in the clamped position clamped about tissue (not shown). For a more detailed description of the operation of the drive assembly 158 and its interaction with the tool assembly, see U.S. Pat. No. 8,132,706.

FIG. 10 illustrates the handle assembly 12 of the stapling device 10 (FIG. 1 ) as the stapling device 10 is fired. When the stapling device 10 is fired, the intermediate spur gear 54 (FIG. 4 ) is engaged with the rack 48 and with the drive gear 56. When the motor assembly 46 is activated, the drive gear 56 rotates the intermediate spur gear 54 to advance the rack 48 in the direction indicated by arrows “A”. The rack 48 is coupled to the firing rod 50 such that advancement of the firing rod 50 causes advancement of the rack 48 to advance the firing rod 50 in the direction of arrows “A” and advance the drive assembly 158 (FIG. 11 ) within the tool assembly 16.

FIG. 11 illustrates the manual retract mechanism 52 as it is readied for use. When the stapling device 10 loses power or gets damaged such that the motor assembly 46 cannot retract the drive assembly 158 to release tissue clamped between the anvil and cartridge assemblies 150 and 152 (FIG. 11 ), the manual retract mechanism 52 can be operated to retract the drive assembly 158 (FIG. 11 ). In order to access the manual retract mechanism 52, the cover 42 (FIG. 1 ) is removed to uncover the upper opening 40 in the housing 18 of the handle assembly 12. Once the cover is removed, the crank lever 80 is pulled upwardly in the direction of arrow “C” to move the crank lever 80 from its lowered position to its raised position. As the crank lever 80 is moved towards its raised position, the first rectangular portion 100 (FIG. 3 ) of the rotating shaft 78 is received in the rectangular portion 86 b (FIG. 3 ) of the through bore 86 in the crank lever 80. Once the first rectangular portion 100 of the rotating shaft 78 is received in the rectangular portion 86 b of the through bore 86 in the crank lever 80, continued movement of the crank lever 80 in the direction of arrow “C” will lift the rotating shaft 78 and the intermediate spur gear 54 to their upper positions compressing the biasing member 120 (FIG. 5 ). In the upper position, the intermediate spur gear 54 is disengaged from the drive gear 56 and is engaged only with the rack 48. Once the crank lever 80 is in its raised position, the grip member 82 can be pivoted in the direction of arrow “D” about the pivot member 94 to an operational position.

Once the crank lever 80 is moved to its raised position, the crank lever 80 can be rotated to rotate the rotating shaft 78 and the intermediate spur gear 54 to retract the rack 48. More specifically, when the crank lever 80 is rotated, receipt of the first rectangular portion 100 (FIG. 3 ) of the rotating shaft 78 in the rectangular portion 86 b of the through bore 86 of the crank lever 80 rotatably fixes the crank lever 80 to the rotating shaft 78. Thus, when the crank lever 80 rotates, the rotating shaft 78 also rotates. The intermediate spur gear 54 is rotatably fixed to the rotating shaft 78 via receipt of the second rectangular portion 104 of the rotating shaft 78 in the rectangular bore 54 a (FIG. 3 ) of the intermediate spur gear 54 such that rotation of the rotating shaft 78 causes rotation of the intermediate spur gear 54. In its upper position, the intermediate spur gear 54 is only engaged with the rack 48, and as such, rotation of the intermediate spur gear 54 causes retraction of the rack 48.

FIGS. 12-13D illustrate an alternate version of the handle assembly 12 (FIG. 2 ) of the stapling device 10 (FIG. 1 ) shown generally as handle assembly 212. The handle assembly 212 includes a housing 214 that is substantially like housing 18 (FIG. 1 ) of stapling device 10. The housing 214 defines a cavity 216 that receives the internal components of the handle assembly 212 and an opening 260 that is enclosed by a cover 262.

The handle assembly 212 includes a motor assembly 220 that is received within the cavity 216 and includes an output shaft (not shown) that rotates a drive gear 222 (FIG. 13B). The motor assembly 220 and the drive gear 222 are substantially like the motor assembly 46 and drive gear 56 described above and will not be described in further detail herein.

The handle assembly 212 includes a gear casing 224 that defines a cavity 226 and a longitudinal channel 228. The drive assembly 218 of the handle assembly 212 includes a spur gear or pinion 230 and a rack 232. The pinion 230 is engaged with the drive gear 222 such that rotation of the drive gear 222 causes rotation of the pinion 230. The pinion 230 is also rotatably supported within the cavity 226 of the gear casing 224 about a shaft 234 and is movable within the cavity 226 between a first position (FIG. 13C) and a second position (13D). The rack 232 extends through the longitudinal channel 228 in the gear casing 224 and includes teeth 232 a that are engaged with the pinion 230 when the pinion 230 is in its first position and disengaged from the pinion 230 when the pinion 230 is in its second position.

The shaft 234 (FIG. 13 ) extends through a non-circular bore 236 defined in the gear casing 224 and includes a head 238, a non-circular shaft portion 240, and a cylindrical portion 242. The non-circular shaft portion 240 of the shaft 234 defines a shoulder 240 a (FIG. 13D) that is positioned adjacent to the circular portion 242 of the shaft 234. The non-circular shaft portion 240 of the shaft 234 is slidably received in the non-circular bore 236 of the gear casing 224 such that the shaft 234 is rotatably fixed to the gear casing 224 but slidable within the non-circular bore 236 between raised and lowered positions. In aspects of the disclosure, the non-circular bore 236 of the gear casing 224 and the non-circular shaft portion 240 of the shaft 234 have corresponding D-shaped configurations although other configurations are envisioned. The cylindrical portion 242 of the shaft 234 defines an annular groove 244 (FIG. 13C).

The pinion 230 defines a central bore 248 (FIG. 13C) that receives and is rotatable about the cylindrical portion 242 of the shaft 234. A biasing member, e.g., a coil spring 250 (FIG. 12 ) is positioned within the cavity 226 of the gear casing 224 between a casing wall 226 a (FIG. 12 ) and a side of the pinion 230 opposite to the head 238 of the shaft 234. The coil spring 250 is in compression and urges the pinion 230 to its first position in which the pinion 230 is engaged with the rack 232. A washer 252 is received within the annular groove 244 formed in the cylindrical portion 242 of the shaft 234. The cylindrical portion 242 of the shaft 234 extends through a bore 256 (FIG. 13C) in a bottom of the gear casing 224, and the washer 252 is positioned externally of the cavity 226 of the gear casing 224 to secure the shaft 234 to the gear casing 224.

When the motor assembly 220 is activated, the drive gear 222 (FIG. 13B) which is engaged with the pinion 230 (FIG. 13C) is rotated to rotate the pinion 230. When the pinion 230 is in its first position engaged with the rack 232 (FIG. 13C), rotation of the pinion 230 causes longitudinal movement of the rack 232. It is noted that the shoulder 240 a of the non-circular portion 240 of the shaft 234 is engaged with the top of the pinion 230 when the pinion 230 is in its first position.

When the stapling device 10 (FIG. 1 ) loses power or gets damaged such that the motor assembly 220 cannot retract the drive assembly 218 to release tissue clamped between the anvil and cartridge assemblies 150 and 152 (FIG. 11 ), the cover 260 (FIG. 12 ) in the housing 214 of the handle assembly 212 can be removed to uncover the opening 262 (FIG. 12 ) in the housing 214 to provide access to the head 238 of the shaft 234. To manually retract the rack 232, the shaft 234 can be pressed downwardly in the direction of arrow “G” in FIG. 13D to move the pinion 230 downwardly within the cavity 226 of the gear casing 224 from its first position to its second position. More particularly, when the shaft 234 is pressed downwardly, the shoulder 240 a on the shaft 234 presses downwardly on the pinion 230 to compress the coil spring 250 and move the pinion 230 to its second position disengaged from the rack 232.

Once the pinion 230 is disengaged from the rack 232, the rack 232 can be pulled or driven proximally using any known retraction means, e.g., a ratchet/pawl mechanism, a hooked tool, or the like, to move the drive assembly 158 of the tool assembly 16 (FIG. 8 ) from the clamped position to the unclamped position. It is noted that additional openings may be created in the housing 214 of the handle assembly 212 to access the retraction means.

FIGS. 14-18 illustrate a stapling device 300 including an alternate version of the handle assembly shown generally as handle assembly 312. The handle assembly 312 includes a housing 314 that is substantially like housing 18 (FIG. 1 ) of stapling device 10 and will not be described in further detail herein. The housing 314 defines a cavity 316 that receives the internal components of the handle assembly 312.

FIGS. 14-16 illustrate the internal components of the handle assembly 312 which includes a motor assembly 318, a drive assembly 320, and a manual retract mechanism 322. The motor assembly 318 is supported within the cavity 316 (FIG. 18 ) of the housing 314 and includes an output shaft 324 that has a flat surface 324 a. In some aspects of the disclosure, the output shaft 324 (FIG. 16 ) has a D-shaped configuration although other configurations are envisioned.

The drive assembly 320 is coupled to the output shaft 324 of the motor assembly 318 and includes a one-way spur gear 328, a drive screw 330, a drive nut 332, connecting rods 334, a coupling member 336, a guide tube 338, and a gear casing 340. The gear casing 340 includes a mounting flange 342 and a cylindrical body 344. The mounting flange 342 of the gear casing 340 defines bores 346 that receive screws 348. The screws 348 are received in threaded bores 350 formed in a distal face of the motor assembly 318 to secure the gear casing 340 to the motor assembly 318. The cylindrical body 344 of the gear casing 340 defines a cavity 352 and a window 354 that communicates with the cavity 352. The cylindrical body 344 of the gear casing 340 defines two openings 356 (only one is shown) and two cutouts 358. One of the openings 356 and one of the cutouts 358 is positioned on each side of the window 354 in vertical alignment with each other. The cavity 352 of the cylindrical body 344 of the gear casing 340 receives the one-way spur gear 328. The distal portion of the cylindrical body 344 of the gear casing 340 supports a bearing 359.

The one-way spur gear 328 defines a central through bore 360 that receives a bearing 362. In aspects of the disclosure, the central through bore 360 and the bearing 362 have corresponding non-circular configurations, e.g., D-shaped configurations, such that the bearing 362 is slidably received within the central through bore 360 of the one-way spur gear 328. The corresponding configurations of the one-way spur gear 328 and the bearing 362 rotatably fix the components to each other. The bearing 362 also defines a central through bore 364 that has a non-circular configuration.

The drive screw 330 includes a threaded outer surface 366, a proximal extension 368, and a distal extension 370. The proximal extension 368 of the drive screw 330 extends through the bearing 359 within the gear casing 340 and is received and secured within the central through bore 364 of the bearing 364. The distal extension 370 of the drive screw 330 is received within a bearing 372 that is supported within the housing 314 (FIG. 16 ) to rotatably support the drive screw 330 within the housing 314.

When the motor assembly 318 is activated to rotate the output shaft 324, rotation of the output shaft 324, when engaged with the one-way spur gear 328, causes corresponding rotation of the one-way spur gear 328. As described above, the one-way spur gear 328 is rotatably fixed to the bearing 362 which is secured to and rotatably fixed to the drive screw 330. As such, rotation of the one-way spur gear 328 causes corresponding rotation of the drive screw 330.

The drive nut 332 includes a threaded bore 374 that receives and is threadably engaged with the threaded outer surface 366 of the drive screw 330. The drive nut 332 is coupled to a proximal portion of the connecting rods 334. In aspects of the disclosure, the drive nut 332 includes protrusions 378 that are received within openings 380 formed in the proximal portions of the connecting rods 334 to connect the drive nut 332 to the connecting rods 334. The connecting rods 334 extend distally from the drive nut 332 and include distal portions that are connected to the coupling member 336. In aspects of the disclosure, the coupling member 336 includes protrusions 384 that are received within openings 386 formed in the distal portions of the connecting rods 334 to connect the coupling member 336 to the connecting rods 334. The drive nut 332 and the connecting rods 334 are received within the guide tube 338.

When the drive screw 330 is rotated, engagement between the outer threaded surface 366 of the drive screw 330 and the inner threaded bore 374 of the drive nut 332 causes the drive nut 332 to translate longitudinally along the drive screw 330 within the guide tube 338. The drive nut 332 is connected to the connecting rods 334 such that longitudinal translation of the drive nut 332 along the drive screw 330 causes the connecting rods 334 to move longitudinally within the guide tube 338 to advance to coupling member 336.

The coupling member 336 is coupled to a firing rod 382 (FIG. 17 ) such that longitudinal movement of the coupling member 336 causes longitudinal movement of the firing rod 382. In aspects of the disclosure, the firing rod 382 includes a head portion 384 and an elongate body 386. The head portion 384 has a diameter that is greater than a diameter of the elongate body 386. The coupling member 336 defines a slot 390 that has a width that is greater than the diameter of the elongate body 386 but less than the diameter of the head portion 384. The elongate body 386 of the firing rod 382 is received through the slot 390 in the coupling member 336 to axially fix the firing rod 382 to the coupling member 336 while allowing relative rotation of the firing rod 382 and the coupling member 336.

The one-way spur gear 328 is movably positioned within the cavity 352 of the cylindrical body 344 of the gear casing 340 between a retracted position (FIG. 17 ) and an advanced position (FIG. 18A). In the retracted position, the one-way spur gear 328 is engaged with the proximal extension 368 of the drive screw 330 and the output shaft 324 of the motor assembly 318 such that rotation of the output shaft 324 of the motor assembly 324 causes rotation of the drive screw 330. In the advanced position, the one-way spur gear 328 is disengaged from the output shaft 324 of the motor assembly 318 but still engaged with the drive screw 330. A biasing member 396, e.g., a coil spring, is positioned between the distal surface of the motor assembly 318 and a proximal surface of the one-way spur gear 328 to urge the one-way spur gear 328 towards the advanced position. In aspects of the disclosure, the proximal surface of the one-way spur gear 328 defines a recess 328 a (FIG. 18A) that receives the biasing member 396.

FIGS. 16-18A illustrate the manual retract mechanism 322 which includes a pawl assembly 410 and a locking clip 412. The pawl assembly 410 includes a handle 414 and a body portion 416. In aspects of the disclosure, the body portion 416 has an oval or annular configuration and supports a ratcheting pawl 418 that is pivotably secured to an upper portion of the body portion 416 by a pivot member 420 (FIG. 16 ). The ratcheting pawl 418 extends downwardly into a circular opening defined by the body portion 416. The body portion 416 is received about the gear casing 340 with the ratcheting pawl 418 positioned over the window 354 in the gear casing 340 above the one-way spur gear 328. A lower portion of the body portion 416 defines a circular slot 422.

The locking clip 412 has a rectangular shape and includes a base portion 426 and spaced legs 428 that extend upwardly from the base portion 426. Each of the legs 428 of the locking clip 412 includes a stepped inner surface 430 that includes a first surface 430 a and a second surface 430 b. The first surfaces 430 a of the legs 428 are spaced to define a first width and the second surfaces 430 b are spaced to define a second width that is greater than the first width. Each of the legs 428 is received through one of the openings 356 and cutouts 358 of the gear casing 340 such that the stepped inner surfaces 430 of the legs 428 of the locking clip 412 are positioned within the cavity 352 of the gear casing 340. The locking clip 412 is movable from a first position in which the first surfaces 430 a of the legs 428 of the locking clip 412 are aligned with the one-way spur gear 328 and a second position in which the second surfaces 430 b of the legs 428 of the locking clip 412 are spaced from the one-way spur gear 328. The width defined between the first surfaces 430 a of the legs 428 of the locking clip 412 is such to prevent movement of the one-way spur gear 328 to its advanced position, whereas the width defined between the second surfaces 430 b of the legs 428 of the locking clip 412 allows movement of the one-way spur gear 328 to the advanced position.

The base portion 426 of the locking clip 412 includes a protrusion 434 (FIG. 16 ) that is received within the circular slot 422 (FIG. 18A) in the body portion 416 of the pawl assembly 410. Receipt of the protrusion 434 couples the pawl assembly 410 to the locking clip 412 to retain the pawl assembly 410 in a stable position about the gear casing 340. The protrusion 434 is configured to slide within the circular slot 422 as described in further detail below.

FIG. 17 illustrates the drive assembly 320 in a pre-fired position with the pawl assembly 410 positioned about the gear casing 340 and the ratcheting pawl 418 positioned above the window 354 (FIG. 16 ) in the gear casing 340. When the handle assembly 312 (FIG. 14 ) is assembled, the one-way spur gear 328 is pressed proximally towards the motor assembly 318 to compress the biasing member 396 and position the one-way spur gear 328 in its retracted position. After the one-way spur gear 328 is in its retracted position, the legs 428 (FIG. 16 ) of the locking clip 412 are inserted from a side of the gear casing 340 opposite to the ratcheting pawl 418 into the openings 356 and cutouts 358 formed in the gear casing 340 to its first position. In the first position of the locking clip 412, the first surfaces 430 a of the legs 428 of the locking clip 412 engage a distal face of the one-way spur gear 328 to retain the one-way spur gear 328 in its retracted position against the urging of the biasing member 396. In its retracted position, the one-way spur gear 328 is engaged with both the output shaft 324 of the motor assembly 318 and the one-way spur gear 328. When the locking clip 412 is in its first position, the protrusion 434 on the locking clip 412 is pressed into the circular slot 422 on the body portion 416 of the pawl assembly 410 to couple the pawl assembly 410 to the locking clip 412 (FIG. 18A).

In the pre-fired position of the handle assembly 12 (FIG. 17 ), the drive nut 332 is positioned near the proximal end of the drive screw 330 and the coupling member 336 is positioned adjacent the distal end of the guide tube 338 such that the connecting rods 334 are in retracted positions and the firing rod 382 is in its retracted position.

FIG. 18A illustrates the handle assembly 312 (FIG. 14 ) in a fired position. When the stapling device 300 (FIG. 14 ) is fired by pressing the actuation buttons 302, the motor assembly 318 (FIG. 16 ) is activated to rotate the output shaft 324. Rotation of the output shaft 324 causes corresponding rotation of the one-way spur gear 328 and the drive screw 330 to advance the drive nut 332 along the drive screw 330 in the direction of arrow “J”. As the drive screw 330 advances the drive nut 332, the drive nut 332 advances the connecting rods 334 to advance the firing rod 382 in the direction of arrow “K” and actuate the tool assembly 306 (FIG. 14 ) as described above regarding tool assembly 16 of the stapling device 10 (FIG. 1 ).

When the tool assembly 316 is in the clamped and fired position (FIG. 8 ) and the powered stapling device 300 (FIG. 14 ) becomes inoperable and cannot be unclamped using the motor assembly 318, the manual retract mechanism 322 allows the tool assembly to be manually unclamped. To operate the manual retract mechanism 322, the pawl assembly 410 is pressed downwardly in the direction of arrow “L” in FIG. 18A. When the pawl assembly 410 is pressed downwardly, the locking clip 412, which is coupled to the pawl assembly 410 by the protrusion 434, is moved from its first position to its second position. In its second position, the locking clip 412 disengages from the one-way spur gear 328 such that the biasing member 396 moves the one-way spur gear 328 from its retracted position to its advanced position. In its advanced position, the one-way spur gear 328 is disengaged from the output shaft 324 of the motor assembly 318. When the pawl assembly 410 is pressed downwardly, the ratcheting pawl 418 moves through the window 354 of the gear housing 340 into engagement with the one-way spur gear 328.

After the one-way spur gear 328 is in its advanced position, the handle 414 of the pawl assembly 410 can be rotated to rotate the one-way spur gear 328 and the drive screw 330 to retract the firing rod 382. As the pawl assembly 410 is rotated, the protrusion 434 (FIG. 18A) moves within the circular slot 422 of the pawl assembly 410.

FIGS. 19-24 illustrate a stapling device 500 including an alternate version of the handle assembly of the stapling device 10 shown generally as handle assembly 512. The handle assembly 512 includes a housing 514 that is substantially like housing 18 (FIG. 1 ) of stapling device 10 and will not be described in further detail herein. The housing 514 defines a cavity 516 that receives the internal components of the handle assembly 512. The cavity 516 is accessible through an opening (not shown) in the housing 514 which is enclosed by a cover (not shown).

The handle assembly 512 includes a motor assembly 520 that is received within the cavity 516 of the handle assembly 512 and includes an output shaft 522 (FIG. 21 ) that rotates a drive gear shown as bevel gear 524. The motor assembly 520 is like the motor assembly 46 described above will not be described in further detail herein.

The handle assembly 512 includes a gear casing 526 that defines a cavity 528 and a longitudinal channel 530. The drive assembly 518 of the handle assembly 512 includes a bevel gear 532 and a rack 534. The bevel gear 532 of the drive assembly 518 is engaged with the bevel gear 524 of the motor assembly 520 such that rotation of the bevel gear 524 causes rotation of the bevel gear 532. The bevel gear 532 is also rotatably supported within the cavity 528 of the gear casing 526 about a shaft 536 and is movable within the cavity 528 between a first position (FIG. 23 ) and a second position (FIG. 24 ). The shaft 536 includes a head 536 a that is positioned adjacent the opening 580 in the housing 514. The rack 534 extends through the longitudinal channel 530 in the gear casing 526 and includes teeth 534 a. The rack 534 includes a distal portion 538 that is coupled to a proximal portion 540 a of a firing rod 540.

The shaft 536 is rotatably supported between two side walls 542 a and 542 b of the gear casing 526 and supports a pinion or spur gear 544. Each of the side walls 542 a and 542 b of the gear casing 526 defines a circular opening 546 (only one is shown) that receives a bearing 548 a, 548 b (FIG. 21 ). The bearings 548 a, 548 b are secured within the openings 546 of the gear casing 526 by retaining plates 550 a and 550 b that are secured to the side walls 542 a and 542 b of the gear casing 526 by screws 552. The bearings 548 define bores 554 that receive the ends of the shaft 536.

The shaft 536 includes a D-shaped portion 556 and defines an annular groove 558 (FIG. 21 ). The D-shaped portion 556 has an end that is received within a D-shaped bore 560 formed in the bevel gear 532 of the drive assembly 518 to secure the shaft 536 to the bevel gear 532 such that rotation of the bevel gear 532 causes rotation of the shaft 536. The D-shaped portion 556 of the shaft 536 is also received within a D-shaped bore 562 formed in the pinion 544 such that rotation of the shaft 536 causes corresponding rotation of the pinion 544. The annular groove 558 in the shaft 536 receives a C-clip 566 to secure the pinion 544 on the shaft 536.

The pinion 544 is secured on the shaft 536 within the cavity 528 of the gear casing 526. The shaft 536 is movable within the bores 554 of the bearings 548 between first and second positions to move the pinion 544 between first and second positions. In the first position of the shaft 536 and the pinion 544 (FIG. 23 ), the pinion 544 is engaged with the teeth 534 a of the rack 534 such that rotation of the pinion 544 causes longitudinal movement of the rack 534 within the longitudinal channel 530 of the gear casing 526. In the second position of the shaft 536 and the pinion 544, the pinion 544 is disengaged from the rack 534. A biasing member, e.g., a coil spring 570, is supported within the cavity 528 of the gear casing 526 between the side wall 542 a of the gear casing 526 and the pinion 544 to urge the pinion 544 towards the first position.

FIGS. 22 and 23 illustrate the drive assembly 518 of the handle assembly 512 (FIG. 19 ) with the shaft 536 and the pinion 544 urged to the first position by the coil spring 570 (FIG. 21 ). As described above, when the shaft 536 and the pinion 544 are in their first positions, the pinion 544 is engaged with the rack 534. When the motor assembly 520 is actuated to rotate the motor assembly bevel gear 524 in the direction of arrow “K” in FIG. 22 , the drive assembly bevel gear 532 is rotated to rotate the shaft 536 in the direction of arrow “L” in FIG. 22 . When the shaft 536 is rotated, the pinion 544 which is secured to the shaft 536 is rotated to move the rack 534 longitudinally in the direction of arrow “M”. The rack 534 is coupled to the firing rod 540. As such, longitudinal movement of the rack 534 causes corresponding longitudinal movement of the firing rod 540 to actuate the tool assembly 16 (FIG. 8 ) as described above.

When the stapling device 500 (FIG. 19 ) loses power or gets damaged such that the motor assembly 520 cannot retract the drive assembly 518 to release tissue clamped between the anvil and cartridge assemblies 150 and 152 (FIG. 11 ), the cover (not shown) in the housing 514 of the handle assembly 512 can be removed to uncover the opening (not shown) in the housing 514 to provide access to the head 536 a of the shaft 536. To manually retract the rack 534, the shaft 536 can be pulled outwardly in the direction of arrow “J” in FIG. 24 to move the pinion 544 within the cavity 528 of the gear casing 526 from its first position to its second position in the direction of arrows “K” and disengage the pinion 544 from the rack 534.

Once the pinion 544 is disengaged from the rack 534, the rack 534 can be pulled or driven proximally using any known retraction means, e.g., a ratchet/pawl mechanism, a hooked tool, or the like, to move the drive assembly 518 of the tool assembly 16 (FIG. 8 ) from the clamped position to the unclamped position. It is noted that additional openings may be created in the housing 514 of the handle assembly 512 to access the retraction means and/or the rack 534.

Persons skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary aspects of the disclosure. It is envisioned that the elements and features illustrated or described in connection with one exemplary aspect of the disclosure may be combined with the elements and features of another without departing from the scope of the disclosure. As well, one skilled in the art will appreciate further features and advantages of the disclosure based on the above-described aspects of the disclosure. Accordingly, the disclosure is not to be limited by what has been particularly shown and described, except as indicated by the appended claims. 

What is claimed is:
 1. A powered handle assembly for a surgical device comprising: a housing defining a first cavity; a gear casing supported within the cavity of the housing, the gear casing defining a second cavity and a longitudinal channel that extends through the second cavity; a motor assembly including an output shaft and a drive gear secured to the output shaft, the motor assembly secured to the gear casing, and the drive gear positioned within the second cavity; a rack received within the longitudinal channel of the gear casing and movable through the second cavity between retracted and advanced positions; a shaft extending through the second cavity, the shaft being axially movable between first and second positions; and a pinion coupled to the shaft and received within the second cavity, the pinion movable within the second cavity, in response to movement of the shaft between its first and second positions, from a first position in which the pinion is directly engaged with the rack to a second position in which the pinion is disengaged from the rack.
 2. The powered handle assembly of claim 1, wherein the shaft is rotatably supported on the gear casing.
 3. The powered handle assembly of claim 1, further including a biasing member positioned within the second cavity, the biasing member positioned to urge the pinion towards its first position.
 4. The powered handle assembly of claim 1, wherein the drive gear is engaged with the pinion such that rotation of the drive gear causes rotation of the pinion.
 5. The powered handle assembly of claim 1, wherein the motor assembly includes a motor having a motor shaft, a universal joint, a joint housing, and the output shaft, the universal joint coupling the motor shaft to the output shaft.
 6. The powered handle assembly of claim 5, wherein the motor shaft defines a first axis and the output shaft defines a second axis, the first axis defining an acute angle with the second axis.
 7. The powered handle assembly of claim 1, wherein the output shaft of the motor assembly supports a first bevel gear and the shaft supports a second bevel gear that is engaged with the first bevel gear such that rotation of the first bevel gear causes rotation of the second bevel gear.
 8. The powered handle assembly of claim 7, wherein the second bevel gear is fixedly secured to the shaft such that rotation of the second bevel gear causes rotation of the shaft and of the pinion.
 9. The powered handle assembly of claim 8, wherein the gear casing includes side walls, each of the side walls supporting a bearing, the shaft rotatably supported between the bearings on the gear casing.
 10. A surgical device comprising: a powered handle assembly including: a housing defining a first cavity; a gear casing supported within the first cavity, the gear casing defining a second cavity and a longitudinal channel that extends through the second cavity; a motor assembly including an output shaft and a drive gear secured to the output shaft, the motor assembly secured to the gear casing, and the drive gear positioned within the second cavity; a rack received within the longitudinal channel of the gear casing and movable through the second cavity between retracted and advanced positions; a shaft extending through the second cavity, the shaft being axially movable between first and second positions; and a pinion coupled to the shaft and received within the second cavity the pinion movable within the second cavity, in response to movement of the shaft between its first and second positions, from a first position in which the pinion is directly engaged with the rack to a second position in which the pinion is disengaged from the rack; an adapter assembly having a proximal portion and a distal portion, the proximal portion coupled to the handle assembly, the adapter assembly including a firing rod that is coupled to the rack and movable between retracted and advanced positions in response to movement of the rack between its retracted and advanced positions; and a tool assembly supported on the distal portion of the adapter assembly.
 11. The surgical device of claim 10, wherein the shaft of the powered handle assembly is rotatably supported on the gear casing.
 12. The surgical device of claim 10, wherein the powered handle assembly further includes a biasing member positioned within the second cavity, the biasing member positioned to urge the pinion towards its first position.
 13. The surgical device of claim 10, wherein the drive gear of the powered handle assembly is engaged with the pinion such that rotation of the drive gear causes rotation of the pinion.
 14. The surgical device of claim 10, wherein the motor assembly of the powered handle assembly includes a motor having a motor shaft, a universal joint, a joint housing, and the output shaft, the universal joint coupling the motor shaft to the output shaft.
 15. The surgical device of claim 14, wherein the motor shaft of the motor assembly of the powered handle assembly defines a first axis and the output shaft of the motor assembly defines a second axis, the first axis defining an acute angle with the second axis.
 16. The surgical device of claim 10, wherein the output shaft of the motor assembly of the powered handle assembly supports a first bevel gear and the shaft supports a second bevel gear that is engaged with the first bevel gear such that rotation of the first bevel gear causes rotation of the second bevel gear.
 17. The surgical device of claim 16, wherein the second bevel gear is fixedly secured to the shaft such that rotation of the second bevel gear causes rotation of the shaft and of the pinion.
 18. The surgical device of claim 17, wherein the gear casing includes side walls, each of the side walls supporting a bearing, the shaft rotatably supported between the bearings on the gear casing.
 19. The surgical device of claim 18, wherein the tool assembly includes an anvil assembly and a cartridge assembly.
 20. A powered handle assembly for a surgical device comprising: a housing defining a cavity; a motor assembly including an output shaft and a drive gear secured to the output shaft; a rack received within the cavity of the housing and movable between retracted and advanced positions; a shaft extending through the cavity, the shaft being axially movable between first and second positions; and a pinion coupled to the shaft, the pinion movable, in response to movement of the shaft between its first and second positions, from a first position in which the pinion is directly engaged with the rack to a second position in which the pinion is disengaged from the rack. 